Formulation of a metal working fluid

ABSTRACT

This invention relates to a composition that is a novel improvement of non-oil containing metal working fluids, also known as synthetic metal working fluids. The invention is a non-oil containing metalworking lubricant composition, having an engineered particle size of greater than 200 nanometers upon dilution. The expansive particle size results in a substantial increase in lubricity, suitable for the heavy-duty operations previously attainable only with oil-containing products. Additionally, this non-oil containing metalworking lubricant incorporates the best of the positive attributes of oil-containing products into its composition, including excellent corrosion inhibition and heavy-duty operation capable lubricity.

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TECHNICAL FIELD

This invention relates to a composition that is a novel improvement ofnon-oil containing metal working fluids, also known as synthetic metalworking fluids. Metal working fluids are classified into two mainsegments, oil containing and non-oil containing. The oil-containingsegment comprises straight oils/soluble oils/semi-synthetics, all ofwhich utilize mineral oil as the primary lubricant. The non-oil segmentis known as synthetics, which use surfactants/polymers/fatty acids asthe main lubricant. The invention consists of an adaptation of syntheticmetal working fluid that demonstrates an engineered increase inlubricity while still providing corrosion protection and microbialcontrol.

BACKGROUND

The water reducible metal working fluids market is primarily segmentedinto two product classes, oil-containing and non-oil containing. Twotypes of products make-up the oil containing line, soluble oils andsemi-synthetics, and both contain mineral oil as their primary lubricityingredient. The non-oil containing products are called synthetics andhave EO/PO polymers, surfactant or fatty acids or combinations thereofas their primary lubricity ingredient.

The soluble oil and semi-synthetic products enjoy an eighty percentshare of the market while the synthetics comprise 10% of the market. Theremaining 10% is held by the non-water reducible straight oils segment.The two existing classifications have advantages and drawbacks. Theoil-containing sectors have the advantages of excellent lubricity, awide range of applications and that the mineral oil provides barrierprotection of sumps from corrosion. The drawbacks of oil-containingmetal working fluids are that water hardness often impacts the fluidstability, that foaming is a frequent problem due to their inclusion ofhigher detergency emulsifiers, in their increased dirt load entrainment,in their increased disposal and tank clean-out impacts and in theirincreased microbial problems.

The current synthetic segment of the metal working fluids market has theadvantage of not having the cleaning issues of oils, having good hardwater stability and microbial control and a long sump life. Thedrawbacks of the existing synthetics are reduced physical lubricity whencompared to oil-containing products on an equal cost basis, increasedsump and machine maintenance corrosion issues, and the potential forskin irritation to those working with the fluid.

The use of synthetics is encouraged for a variety of factors fromenvironmental issues to the microbial advantages. However, mostcustomers continue to use oil containing products because of their goodlubricity at a low comparative cost, and because of the increasedmaintenance corrosion issues associated with synthetics. Syntheticsumps, lacking the protective barrier film provided by oil, can corrodeand “freeze” machining system bolts, making maintenance difficult.Additionally, high lubricity performance synthetic products areexpensive when compared with similar lubricity performance oilcontaining products. Their reduced physical lubricity on a cost basiswith semi-synthetics restrains their use in heavy-duty operations.

The current invention has developed an entirely new class of metalworking fluid products. This new chemistry incorporates a synergisticblend of carboxylic acid salts/boundary lube fatty acids and EO/POpolymers, which at an optimized pH range react to form a moiety withenhanced particle size and exceptional lubricity. In addition, usedilutions are opaque and mimic the appearance of oil-based solutions.

DETAILED DESCRIPTION Definitions Metalworking

Metalworking is the shaping of metallic work-pieces to conform to adesired set of geometric specifications. Metalworking comprises twobasic categories, cutting and forming. Cutting operations includegrinding, turning, milling, tapping, broaching and hobbing. Formingoperations include hot and cold rolling, drawing, forging, stamping andblanking.

Metalworking fluids are essential in both cutting and formingoperations. They must provide for lubrication between the work-piece andtool and also provide cooling by removing the heat generated during themetalworking operations.

Lubricants—Polymeric Lubricity Agents

Lubrication is defined as the reduction of friction between two movingsurfaces. The two main types of lubrication in metalworking operationsare hydrodynamic and boundary/extreme pressure (EP). Hydrodynamiclubrication involves separating the moving surfaces by a film of fluidlubricant. Boundary/EP lubrication minimizes the wear experienced whensurfaces rub together. polymeric lubricity agents can provide both typesof lubrication.

These can be comprised of one or more of the following: block copolymersconsisting of a central polyoxypropylene block with a polyoxyethylenechain at either end, block copolymers consisting of a centralpolyoxyethylene block with a polyoxypropylene chain at either end,tetrablock copolymers derived from the sequential addition of ethyleneoxide and propylene oxide to ethylenediamine, ethylene oxide/propyleneoxide copolymers having at least one terminal hydroxyl group,water-soluble lubricant base stocks of random copolymers of ethyleneoxide and propylene oxide, a water-soluble polyoxyethylene orpolyoxypropylene alcohol or a water-soluble carboxylic acid ester ofsuch alcohol, alcohol-started base stocks of all polyoxypropylene groupswith one terminal hydroxyl group, monobasic and dibasic acid esters,polyol esters, polyalkylene glycol esters, polyalkylene glycols graftedwith organic acids, phosphate esters, polyisobutylenes,polyacrylonitriles, polyacrylamides, polyvinylpyrrolidones, polyvinylalcohols and copolymers of acrylic acid or methacrylic acid and anacrylic ester.

Carboxylic Acid Salts

Partially neutralized carboxylic acids salts provide a lipophilic moietyfor the polymeric lubricity agents to network with and provide for theengineering of a larger particle size. The pH of the partialneutralization is dependent upon the alkaline agent used. Many of thesecarboxylic acid salts additionally provide their own boundarylubrication as well. The carboxylic acids can be linear or branched,saturated or unsaturated, fatty or oil, animal or vegetable, cis ortrans configured, dicarboxylic, tricarboxylic, esterified, amines,amides, or ethoxylated. The following are some of the examples of thecarboxylic acids: caproic/hexanoic acid, enanthic/heptanoic acid,caprylic/octanoic acid, pelargonic/nonionic acid, isononanoic acid,capric/decanoic acid, neodecanoic acid, lauric/dodecanoic acid,stearic/octadecanoic acid, arachidic/eicosanoic acid,palmitic/hexadecanoic acid, erucic acid, oleic acid, arachidonic acid,linoleic acid, linolenic acid, myristic/tetradecanoic acid,behenic/docosanoic acid, alpha-linolenic acid, docosahexaenoic acid,ricinoleic acid, butyric acid, lard oil, tallow oil, butter, coconutoil, palm oil, cottonseed oil, wheat germ oil, soya oil, olive oil, cornoil, sunflower oil and rapeseed/canola oil.

Emulsifying/Dispersing Agents

Dilutions of the metalworking fluid composition result in an opaqueemulsion. At concentrations above 10%, the emulsion requiresstabilization. Emulsifying/dispersing agents provide stabilization ofthe engineered large particle emulsion. The emulsifying/dispersingagents may be one or more of the following: alkanolamides, alkylarylsulfonates, alkylaryl sulfonic acids, amine oxides, amide and aminesoaps, block copolymers, carboxylated alcohols, carboxylic acids/fattyacids, ethoxylated alcohols, ethoxylated alkylphenols, ethoxylatedamines/amides, ethoxylated fatty acids, ethoxylated fatty esters andoils, ethoxylated phenols, fatty amines and esters, glycerol esters,glycol esters, imidazolines and imidazoline derivatives, lignin andlignin derivatives, maleic or succinic anhydrides, methyl esters,monoglycerides and derivatives, naphthenic acids, olefin sulfonates,phosphate esters, polyalkylene glycols, polyethylene glycols, polyols,polymeric (polysaccharides, acrylic acid, acrylamide), propoxylated &ethoxylated fatty acids, alcohols or alkyl phenols, quaternarysurfactants, sarcosine derivatives, soaps, sorbitan derivatives, sucroseand glucose esters and derivatives, sulfates and sulfonates of oils andfatty acids, sulfates and sulfonates ethoxylated alkylphenols, sulfatesof alcohols, sulfates of ethoxylated alcohols, sulfates of fatty esters,sulfonates of dodecyl and tridecylbenzenes, sulfonates of naphthaleneand alkyl naphthalene, sulfonates of petroleum, sulfosuccinamates,sulfosuccinates and derivatives, tridecyl and dodecyl benzene sulfonicacids.

Corrosion Inhibiting Component

Oil-containing products rely heavily on the oil itself to form a barriercoating of corrosion protection. Non-oil containing products need toattain this corrosion protection by chemical means. A corrosioninhibitor is a chemical compound that, when added in smallconcentration, stops or slows down the corrosion of metals and alloys.

Some of the mechanisms for the corrosion inhibitors effect are theformation of a passivation layer (a thin film on the surface of thematerial that stops access of the corrosive substance to the metal),inhibiting either the oxidation or reduction part of the redox corrosionsystem (anodic and cathodic inhibitors), or scavenging the dissolvedoxygen. There are many different compostions that fall into this group.Some examples are alkali and alkanolamine salts of carboxylic acids,undecandioic/dodecandioic acid and its salts, C₄₋₂₂ carboxylic acids andtheir salts, boric acids, compounds and their salts, tolytriazole andits salts, benzotriazoles and its salts, imidazolines and its salts,alkanolamines and amides, sulfonates, alkali and alkanolamine salts ofnaphthenic acids, phosphate ester amine salts, alkali nitrites, alkalicarbonates, carboxylic acid derivatives, alkylsulfonamide carboxylicacids, arylsulfonamide carboxylic acids, fatty sarkosides, phenoxyderivatives and sodium molybdate.

Alkalinity Agents

Alkalinity Agents provide for the desired pH of the product and, in somecases for reserve alkalinity and pH buffering. Examples of thealkalinity agents include but are not limited to alkanolamines—primary,secondary and tertiary, aminomethylpropanol (AMP-95), diglycolamine(DGA), monoethanolamine (MEA), monoisopropanolamine (MIPA),butylethanolamine (NBEA), dicylclohexylamine (DCHA), diethanolamine(DEA), butyldiethanolamine (NBDEA), triethanolamine (TEA), metal alkalihydroxides, potassium hydroxide, sodium hydroxide, magnesium hydroxide,lithium hydroxide, metal carbonates and bicarbonates, sodium carbonate,sodium bicarbonate, potassium carbonate and potassium bicarbonate.

The claimed invention has many attributes that make it varied fromexisting products. The fact that it is a synthetic product whichincorporates the attributes of an oil-based product is novel. Thepositive attributes of currently available non-oil products aremaintained in this composition as well and include environmentalcompliance, good cooling, good chip removal/settling characteristics,long sump life and good biological resistance.

The current invention is a non-oil containing metal working fluidcomposition consisting of a volume average particle size of 125 nm orgreater when diluted between 0.1 and 50 percent, comprised of one ormore polymeric lubricity agent(s), one or more carboxylic acid salt(s),one or more emulsifying/dispersing agent(s), a transport component whichcan be water and one or more corrosion inhibiting component(s). Theinvention has a pH of 3 or greater and may also include an alkalinityagent which can be one or more of the following a primary, secondary,tertiary and quaternary alkanolamine and can be a metal alkalihydroxide. The invention can also contain an anti-foaming agent and/or abiocide and a fungicide.

In the claimed invention, the working metal fluid composition, whendiluted between 0.1 and 50 percent comprises a lubricity, measured bytapping torque instruments, of less than 8000 Newton-cm⁻¹.

It should be understood that nothing in the preceding description ismeant to limit the scope of the invention as described in the claims.The description is only a sampling of the components of the inventionand a sampling of the embodiment and additional embodiments are in noway limited or excluded because there is no mention of such embodiments.Any changes and modifications can be made without departing from thespirit and scope of the invention and without diminishing its intendedadvantages. It is therefore intended that such changes and modificationsbe covered by the appended claims

SUMMARY

The current invention describes the following key aspects:

-   -   1. It is an advantage of the invention to achieve the lubricity        of oil containing products, using surfactants/polymers.    -   2. It is an advantage of the invention to achieve a        lubricity/cost performance point approaching that of oil        containing products.    -   3. It is an advantage of the invention to reduce worker        irritation associated with higher pH.    -   4. It is an advantage of the invention to achieve rust        protection of oil containing products    -   5. Ability to have an alkanolamine free chemistry.

EXAMPLES

The foregoing may be better understood by reference to the followingexamples, which are intended to illustrate methods for carrying out theinvention and are not intended to limit the scope of the invention.

It should be understood that various changes and modifications to thepresently preferred embodiments described herein will be apparent tothose skilled in the art. Such changes and modifications can be madewithout departing from the spirit and scope of the invention and withoutdiminishing its intended advantages. It is therefore intended that suchchanges and modifications be covered by the appended claims.

Example 1

Material A B C D E Pluronic “R” 0% 10% 20% 20% 20% block copolymerCarboxylic 10% 10% 10% 5% 0% acid - alkali salts Emulsifiers 5% 5% 5% 5%5% Corrosion 4% 4% 4% 4% 4% inhibitors RO water Remainder RemainderRemainder Remainder Remainder

The materials of example 1 were employed in a tapping torque operationinvolving the tapping of 6061 aluminum. The concentrates were firstdiluted to a 7.5% by volume solution before testing. The tapping torquetest is a quantitative measure of the lubricity performance ofmetalworking fluids. It has an ASTM standard method designation ofD5619. Tapping torque reflects the industrial machining process in abetter way than other tests, which commonly consist of rubbing twometals together. It is an excellent method of discriminating MWF productmachining performance in the laboratory. Tapping Torque results havebeen proven to correlate well with field machining performance.

The tapping torque instrument is designed to measure the lubricity ofMWFs while actual cutting is performed. During the tapping operation,the Tapping Torque instrument measures the instantaneous torque 250times as the tap advances throughout the depth of the cut. Specializedsoftware then facilitates data analysis. Tapping torque is expressed inunits of N-m (Newton-meters) or N-cm (Newton-centimeters). Products withhigh lubricity will generate lower torque values. Conversely, lowlubricity products will generate high torque values. In this way theinstrument quantifies the differences in lubrication performance betweenproducts.

One drawback of the tapping torque instrument is in that the absolutetorque values measured are dependent upon and will vary with thediameter of the tap used. Therefore, in order to cancel out thesegeometric effects it is efficacious to express the lubricity as thetorque per area to describe the energy it takes for a tap to make onerevolution. The equation for this is E/A=(2τ)/r², where τ=torque value,r=the radius of the tap, E/A=energy per area and the units are N-m⁻¹(Newtons per meter) or N-cm⁻¹ (Newtons per centimeter).

The data is presented in table form and the lubricity is depicted asE/A. The lower the E/A value, the better the lubricity and machiningperformance. All samples were diluted with water to 7.5% by volumebefore testing.

Material A B C D E Lubricity - E/A (N- 6259 4285 3713 4233 5921 cm⁻¹)

Example 2

Material A B C D E Pluronic “R” 0% 10% 20% 20% 20% block copolymerCarboxylic 10% 10% 10% 5% 0% acid - alkali salts Emulsifiers 5% 5% 5% 5%5% Corrosion 4% 4% 4% 4% 4% inhibitors RO water Remainder RemainderRemainder Remainder Remainder

The materials of example 2 were employed in a particle size operationinvolving the measurement of the volume average particle size innanometer units. The concentrates were first diluted with water to a7.5% by volume solution before testing. The particle-sizing instrumentuses high efficiency dynamic light scattering to quantify particle sizesof 20 to 100,000 nanometers.

All samples were diluted to 7.5% by volume before testing.

Material A B C D E Volume Average 120 140 350 220 20 Particle Size(nanometers)

Example 3

Volume Average Concentration Particle Size Emulsion Material (by volume)(nanometers) Appearance Stability C from Example 1 7.5% 350 Milkywhite - Excellent opaque C from Example 1 15.0% 2000 Milky white -Excellent opaque

SUMMARY

From examples 1-3 it is seen that optimal lubricity and particle size isobtained with sample C which combines 10% carboxylic acid—alkali saltsand 20% Pluronic “R” block copolymer. This ratio gives the maximumvolume average particle size and maximum lubricity.

Typical synthetic MWFs, when diluted, form clear solutions with particlesize of less than 100 nanometers. Dilutions of sample C are milky-whiteopaque and as seen in examples 2 and 3, have particle sizes 3.5 to 20times larger than the maximum size seen with typical synthetic MWFs.

It is also apparent from the examples that to a large degree, thelubricity is a function of its volume average particle size. Increasingvolume average particle size results in increased lubricity.

From example 3 it is seen that increased concentration of sample Cresults in significantly larger volume average particle size. Thisexplains the necessity of emulsifiers to stabilize higher concentrationsof sample C. Without emulsifiers, the particle size of higherconcentrations would continue to agglomerate to an unstable state.

1. A metal working fluid composition with a volume average particle sizeof 125 nm or greater when diluted between 0.1 and 50 percent comprisedof: (a) one or more polymeric lubricity agent; (b) one or morecarboxylic acid salt; (c) one or more emulsifying/dispersing agent; (d)a transport component.
 2. The composition of claim 1 including one ormore oils at less than 10 percent.
 3. The composition of claim 1 whereinthe transport component is water.
 4. The composition of claim 1including a corrosion inhibiting component.
 5. The composition of claim4 wherein the corrosion inhibiting component consisting of one or moreof the following: alkali and alkanolamine salts of carboxylic acids,undecandioic/dodecandioic acid and its salts, C₄₋₂₂ carboxylic acids andtheir salts, boric acids, compounds and their salts, tolytriazole andits salts, benzotriazoles and its salts, imidazolines and its salts,alkanolamines and amides, sulfonates, alkali and alkanolamine salts ofnaphthenic acids, phosphate ester amine salts, alkali nitrites, alkalicarbonates, carboxylic acid derivatives, alkylsulfonamide carboxylicacids, arylsulfonamide carboxylic acids, fatty sarkosides, phenoxyderivatives and sodium molybdate.
 6. The composition of claim 1 whereinthe pH is 3 or greater.
 7. The composition of claim 1 including analkalinity agent.
 8. The composition of claim 7 wherein the alkalinityagent is one or more of the following: alkanolamines—primary, secondaryand tertiary, aminomethylpropanol (AMP-95), diglycolamine (DGA),monoethanolamine (MEA), monoisopropanolamine (MIPA), butylethanolamine(NBEA), dicylclohexylamine (DCHA), diethanolamine (DEA),butyldiethanolamine (NBDEA), triethanolamine (TEA), metal alkalihydroxides, potassium hydroxide, sodium hydroxide, magnesium hydroxide,lithium hydroxide, metal carbonates and bicarbonates, sodium carbonate,sodium bicarbonate, potassium carbonate and potassium bicarbonate. 9.The composition of claim 7 wherein the alkalinity agent is a metalalkali hydroxide.
 10. The composition of claim 1 including an antifoaming agent.
 11. The composition of claim 1 including a biocide and/ora fungicide.
 12. The composition of claim 1 wherein the polymericlubricity agent is a block copolymer.
 13. The composition of claim 12wherein the polymeric lubricity agent is one or more of the following:block copolymers consisting of a central polyoxypropylene block with apolyoxyethylene chain at either end, block copolymers consisting of acentral polyoxyethylene block with a polyoxypropylene chain at eitherend, tetrablock copolymers derived from the sequential addition ofethylene oxide and propylene oxide to ethylenediamine, ethyleneoxide/propylene oxide copolymers having at least one terminal hydroxylgroup, water-soluble lubricant base stocks of random copolymers ofethylene oxide and propylene oxide, a water-soluble polyoxyethylene orpolyoxypropylene alcohol or a water-soluble carboxylic acid ester ofsuch alcohol, alcohol-started base stocks of all polyoxypropylene groupswith one terminal hydroxyl group, monobasic and dibasic acid esters,polyol esters, polyalkylene glycol esters, polyalkylene glycols graftedwith organic acids, phosphate esters, polyisobutylenes,polyacrylonitriles, polyacrylamides, polyvinylpyrrolidones, polyvinylalcohols and copolymers of acrylic acid or methacrylic acid and anacrylic ester.
 14. The composition of claim 12 wherein the blockcopolymer is polypropylene glycol block copolymer.
 15. The compositionof claim 12 wherein the block copolymer is polyethylene glycol blockcopolymer.
 16. The composition of claim 12 wherein the block copolymeris polyethylene glycol/polypropylene glycol block copolymer.
 17. Thecomposition of claim 1 wherein the one or more carboxylic acid salt isan alkali and/or alkanolamine salts of C₄-C₂₂ carboxylic/fatty acids andesters.
 18. The composition of claim 1 wherein the carboxylic acid saltis comprised of one or more of the following: caproic/hexanoic acid,enanthic/heptanoic acid, caprylic/octanoic acid, pelargonic/nonionicacid, isononanoic acid, capric/decanoic acid, neodecanoic acid,lauric/dodecanoic acid, stearic/octadecanoic acid, arachidic/eicosanoicacid, palmitic/hexadecanoic acid, erucic acid, oleic acid, arachidonicacid, linoleic acid, linolenic acid, myristic/tetradecanoic acid,behenic/docosanoic acid, alpha-linolenic acid, docosahexaenoic acid,ricinoleic acid, butyric acid, lard oil, tallow oil, butter, coconutoil, palm oil, cottonseed oil, wheat germ oil, soya oil, olive oil, cornoil, sunflower oil and rapeseed/canola oil.
 19. The composition of claim1 wherein the emulsifying/dispersing agent is one or more of thefollowing: alkanolamides, alkylaryl sulfonates, alkylaryl sulfonicacids, amine oxides, amide and amine soaps, block copolymers,carboxylated alcohols, carboxylic acids/fatty acids, ethoxylatedalcohols, ethoxylated alkylphenols, ethoxylated amines/amides,ethoxylated fatty acids, ethoxylated fatty esters and oils, ethoxylatedphenols, fatty amines and esters, glycerol esters, glycol esters,imidazolines and imidazoline derivatives, lignin and lignin derivatives,maleic or succinic anhydrides, methyl esters, monoglycerides andderivatives, naphthenic acids, olefin sulfonates, phosphate esters,polyethylene glycols, polyols, polymeric (polysaccharides, acrylic acid,acrylamide), propoxylated & ethoxylated fatty acids, alcohols or alkylphenols, quaternary surfactants, sarcosine derivatives, soaps, sorbitanderivatives, sucrose and glucose esters and derivatives, sulfates andsulfonates of oils and fatty acids, sulfates and sulfonates ethoxylatedalkylphenols, sulfates of alcohols, sulfates of ethoxylated alcohols,sulfates of fatty esters, sulfonates of dodecyl and tridecylbenzenes,sulfonates of naphthalene and alkyl naphthalene, sulfonates ofpetroleum, sulfosuccinamates, sulfosuccinates and derivatives, tridecyland dodecyl benzene sulfonic acids.
 20. The composition of claim 1wherein the metalworking fluid composition, when diluted between 0.1 and50 percent comprises a lubricity, as measured by tapping torqueinstruments, of less than 8000 Newton-cm⁻¹.
 21. A metal working fluidcomposition comprised of: (a) 1 to 80 percent one or more blockcopolymers; (b) 1 to 40 percent one or more carboxylic acid salts; (c) 1to 20 percent of one or more emulsifying agents; (d) a transportcomponent.
 22. A metal working fluid composition comprised of: (a) 5 to40 percent one or more block copolymers; (b) 3 to 30 percent one or morecarboxylic acid salts; (c) 2 to 12 percent of one or more emulsifyingagents; (d) a transport component.
 23. A metal working fluid compositioncomprised of: (a) 15 to 25 percent one or more block copolymers; (b) 5to 15 percent one or more carboxylic acid salts; (c) 3 to 8 percent ofone or more emulsifying agents; (d) a transport component.